[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) › Opponens pollicis [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) # Opponens pollicis The opponens pollicis is a deep thumb-pad muscle; it rolls the thumb across the palm to meet the fingers, a movement called opposition. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=upper_limb&select=opponens_pollicis&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A deep thumb-pad muscle along the thumb metacarpal. ## What it does Rolls the thumb across the palm to meet the fingers (opposition). ## Key points - Lies deep to APB and FPB and is the only thenar muscle that inserts on the metacarpal, along its whole lateral border - Opposition combines abduction, flexion and medial rotation at the thumb CMC joint; this muscle supplies the rotation - Ape hand: thenar wasting with the thumb lying back in line with the fingers, unable to rotate to face them ## Key facts **Origin** Flexor retinaculum, tubercle of the [trapezium](https://durgical.com/en/anatomy/trapezium/) **Insertion** Lateral border of the 1st metacarpal **Action** Opposes the thumb (rotates it to face the fingers) **Nerve** Recurrent branch of the [median nerve](https://durgical.com/en/anatomy/median-nerve/) (C8–T1) **Blood supply** Superficial palmar branch of the [radial artery](https://durgical.com/en/anatomy/radial-artery/) ## Relations **Superficial** [Abductor pollicis brevis](https://durgical.com/en/anatomy/abductor-pollicis-brevis/) (APB) and part of the [flexor pollicis brevis](https://durgical.com/en/anatomy/flexor-pollicis-brevis/) (FPB) **Deep** The [1st metacarpal](https://durgical.com/en/anatomy/1st-metacarpal/) and the capsule of the thumb CMC joint **Medial** Deep head of FPB and the [adductor pollicis](https://durgical.com/en/anatomy/adductor-pollicis/) ## How to find it Being deep, it is felt through APB: touching the thumb pad to the little-finger pad, nails parallel, makes the thenar eminence harden along the thumb metacarpal. ## Examination - Opposition test: the thumb pad is brought to the little-finger pad with the nails parallel; contact only with the side of the thumb, without rotation, indicates a median nerve or [recurrent motor branch](https://durgical.com/en/anatomy/recurrent-motor-branch-of-the-median-nerve/) lesion ## On imaging Lies deep to abductor pollicis brevis along the thumb metacarpal; ultrasound and MRI show it as the deep thenar layer. Rarely the target itself: imaging looks for median nerve compression at the wrist, and MRI may show thenar denervation (oedema, then fatty atrophy). Thumb-base radiographs assess trapeziometacarpal arthritis, which limits the same motion. ## Clinical notes - Ape hand follows a median nerve lesion, most clearly when high (with long flexor loss too); the extensors pull the thumb back in line with the fingers - Opponensplasty restores opposition when the recurrent motor branch or median nerve does not recover ## Anatomical variants - Sometimes supplied by the [ulnar nerve](https://durgical.com/en/anatomy/ulnar-nerve/), through a palmar link between the deep branch of the ulnar nerve and the recurrent motor branch (Riche–Cannieu anastomosis), which can preserve opposition after a median injury ## Development Thenar muscles are among the parts most affected in congenital thumb hypoplasia: beyond the mildest grades, opponens pollicis and abductor pollicis brevis are small or missing, so an opposition transfer is part of the repair. The thumb comes to lie laterally because the [upper limb](https://durgical.com/en/anatomy/region/upper-limb/) turns outward by about 90° in week 7. ## Related conditions - [Carpal tunnel syndrome](https://durgical.com/en/conditions/carpal-tunnel-syndrome/) ## Test yourself Think of the answer, then tap the question to see it. ## Which thenar muscle inserts on the metacarpal, and what movement does it supply? The opponens pollicis, along the whole lateral border of the 1st metacarpal; it supplies the rotation of opposition. ## What is an ape hand? Thenar wasting with the thumb lying back in line with the fingers, unable to rotate to face them; it follows a median nerve lesion. ## How is opposition tested, and what does a positive result mean? Thumb pad to little-finger pad with the nails parallel; contact only with the side of the thumb indicates a median nerve or recurrent motor branch lesion. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/opponens-pollicis/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** musculus opponens pollicis TA2 2525 **Official Spanish (DeCS)** Músculo oponente del pulgar **English (TA2)** Opponens pollicis ## Related - [Recurrent motor branch](https://durgical.com/en/anatomy/recurrent-motor-branch-of-the-median-nerve/) - [Deep palmar arch](https://durgical.com/en/anatomy/deep-palmar-arch/) - [1st metacarpal](https://durgical.com/en/anatomy/1st-metacarpal/) - [Thumb sesamoids](https://durgical.com/en/anatomy/sesamoid-bones-of-the-thumb/) - [Trapezium](https://durgical.com/en/anatomy/trapezium/) Sources: Terminologia Anatomica (TA2); [Anatomy, Shoulder and Upper Limb, Hand Opponens Pollicis Muscle](https://www.ncbi.nlm.nih.gov/books/NBK546603/); [8.5 Development of the Appendicular Skeleton](https://openstax.org/books/anatomy-and-physiology-2e/pages/8-5-development-of-the-appendicular-skeleton) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/opponens-pollicis/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/opponens-pollicis/